They had to Bypass it, and use their own compressor for the final mix down
I tried to give the short answer and failed.
Here we go...
For any pro project, I would almost never use the compressor in the Genos. The effects software and hardware in a top-notch studio dwarf just about anything in the Genos, even if it's just flexibility and not sound quality. Many of the effects in the Genos are pretty laughable from a pro studio perspective. That's not to say they're not workable, as they certainly can be. I've done (and heard) some impressive recordings that were done with nothing but the Genos.
However, if I sat you down in the producer's chair in the control room and demonstrated comparisons, in many cases you'd be blown away by the difference. I'm not talking esoteric, audiophile-only, barely-perceptible differences either.
That doesn't make the Genos bad by ANY means, as the internal effects are one of the big reasons I got one. It's super convenient and I don't want to haul around heavy and expensive racks of effects gear. But, when I take it into a studio, look out!
(Many studio hardware effects and audio processors cost more than a Genos and are only 19" wide and easily fit in two hands.)
As for the compressor, I've heard the issue with it. I haven't had time to dig into it very deeply yet. However, I
suspect it's either more of a limiter or contains a limiter stage in the output. It may even be a multi-band limiter. Either way, this type of effect does something similar to compression but also increases perceived loudness as it pushes the softer sounds up towards a set output ceiling.
Picture an upside down espresso press. As you push the coffee up it compresses against the top of the press but can never go higher than the top of the press. In the process, the coffee simply gets squishier and squishier (complicated pro terminology).
So, technically there
is some compression going on but it's also pushing up the overall loudness. If you push it far enough you suck out all the dynamics of the music and potentially introduce distortion. Try turning up the Master Compressor to its maximums and I'll bet you run into this.
*At it's most basic, a compressor both increases the volume of softer sounds and turns down the volume of louder ones bringing each of them closer to each other. (There's more to a compressor but this is the pertinent point at the moment.) The initial result is typically a drop in overall volume, which you then need to compensate for by adding more overall volume, known as makeup gain.
So, it's easy to see how your engineers would see that it's supposed to be a master compressor but only hear the results of what's likely a limiter and chose to go with the house gear. Good choice too.
*The overuse of limiters has done a lot of damage to music over the last several years, giving rise to what is known as
The Loudness Wars. I co-founded an organization to help educate consumers and give engineers a platform to reform the industry. If you're interested in more info please visit
http://www.TurnMeUp.org There's a great video there demonstrating a lot of this in easy to understand terms.